Among various displays such as a liquid crystal display (LCD) using electro-optical effect, a plasma display panel (PDP) using gas discharge and an electro-luminescence display (ELD) device using field emission effect, LCDs are most actively being researched.
Since LCDs are a receive optical device in which images are displayed by controlling light amount inputted from an outside, they essentially need a separate light source, i.e., backlight device, for irradiating an LCD panel.
Such a backlight unit uses a light emitting diode (LED) and a light emitting lamp such as a cold cathode fluorescent lamp (CCFL).